Electron-cyclotron-current-drive experiments in the DIII-D tokamak

James, R. A.; Giruzzi, G.; Gentile, B. De; Rodrı́guez, L.; Harvey, R. W.; Lohr, J.; Luce, T. C.; Matsuda, Kyoko; Moeller, C.P.; Prater, R.; Snider, R. T.; Fyakhretdinov, A.; Gorelov, Yu. A.; Trukhin, V. M.; Janz, S. J.

doi:10.1103/physreva.45.8783

Cited by 43 publications

(27 citation statements)

References 10 publications

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“…The current I is then compared to the current I EC that would be driven by ECCD alone in the same plasma conditions, which can be evaluated by means of standard toroidal ray-tracing codes, coupled to a Fokker-Planck code or, more simply, to linear expressions of the current drive efficiency [17], which is completely appropriate to this power level. These theoretical expressions have been fully validated by a dedicated series of experiments, performed on the DIII-D tokamak in a variety of different plasma conditions [18][19][20]: they can be used as a reliable reference for the ECCD efficiency in conditions of strong single pass absorption and good confinement of the current carrying electrons. The synergy effect can be quantified, e.g., by the synergy factor [11] defined as F syn I=I EC , where I I LHEC ÿ I LH .…”

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confidence: 98%

Synergy of Electron-Cyclotron and Lower-Hybrid Current Drive in Steady-State Plasmas

et al. 2004

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Improvement (up to a factor of approximately 4) of the electron-cyclotron (EC) current drive efficiency in plasmas sustained by lower-hybrid (LH) current drive has been demonstrated in stationary conditions on the Tore Supra tokamak. This was made possible by feedback controlled discharges at zero loop voltage, constant plasma current, and constant density. This effect, predicted by kinetic theory, results from a favorable interplay of the velocity space diffusions induced by the two waves: the EC wave pulling low-energy electrons out of the Maxwellian bulk, and the LH wave driving them to high parallel velocities.

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confidence: 98%

Synergy of Electron-Cyclotron and Lower-Hybrid Current Drive in Steady-State Plasmas

et al. 2004

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“…programs are underway on DIII-D on fast wave current drive (FWCD) [3,4] and electron cyclotron current drive (ECCD) [5] to develop means of controlling the current profile. The FWCD tends to be deposited where the electron temperature is highest, which is near the center of the discharge.…”

Section: Methodsmentioning

confidence: 99%

Non-inductive current drive experiments on DIII - D, and future plans

Prater

Austin

Baity

et al. 1995

Fusion Engineering and Design

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I w ,t°o DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe priwtely owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. AbstractExperimentson DIII-D (andothertokamaks)have shown thatimprovedperformance can follow from optimization ofthecurrent density profile. Increased confinement ofenergy and a higherlimiton betahave bothbeen foundindischarges inwhichthe current density profile ismodified throughtransient means,suchasrampingofcurrent orelongation. Peaking

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“…In principle these could be obtained from inspection of Q EC (f M ), but are more easily obtained from an analysis of the results of a time dependent bounce-averaged quasi-linear Fokker-Planck calculation [23]. In regimes where the assumption of a linear response breaks down [24], full bounce-averaged quasi-linear Fokker-Planck calculations may also be used to parameterize the nonlinear de-pendence of the current drive efficiency η EC including its predicted synergy with the (orbit averaged) parallel electric field [2,25].…”

Section: B a New Closure Relation For The Ec Driven Current Densitymentioning

confidence: 99%

Closure of the single fluid magnetohydrodynamic equations in presence of electron cyclotron current drive

Westerhof

Pratt

Ayten

2015

EPJ Web of Conferences

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Abstract. In the presence of electron cyclotron current drive (ECCD), the Ohm's law of single fluid magnetohydrodynamics (MHD) is modified as E + v × B = η(J − J ECCD ). This paper presents a new closure relation for the EC driven current density appearing in this modified Ohm's law. The new relation faithfully represents the nonlocal character of the EC driven current and its main origin in the Fisch-Boozer effect. The closure relation is validated on both an analytical solution of an approximated Fokker-Planck equation as well as on full bounce-averaged, quasi-linear Fokker-Planck code simulations of ECCD inside rotating magnetic islands.

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Electron-cyclotron-current-drive experiments in the DIII-D tokamak

Cited by 43 publications

References 10 publications

Synergy of Electron-Cyclotron and Lower-Hybrid Current Drive in Steady-State Plasmas

Synergy of Electron-Cyclotron and Lower-Hybrid Current Drive in Steady-State Plasmas

Non-inductive current drive experiments on DIII - D, and future plans

Closure of the single fluid magnetohydrodynamic equations in presence of electron cyclotron current drive

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